Micro. Final exam

What are the contributions Joseph lister?

developed aseptic surgery to sterilize instruments and sanitize wounds with carbolic acid to encourage healing and prevent pus formation

how did Robert Koch help shape the germ theory of disease

developed staining techniques and ways to grow and isolate bacteria.

Robert Koch's postulates of disease

-The same organism must be present in every case of the disease.

-The organism must be isolated from the diseased host and grown as a pure culture.

-The isolated organism should cause the disease in question when it is introduced (inoculated) into a susceptible host

-The organism must then be re-isolated from the inoculated, diseased animal.

What information does the binomial nomenclature provide about an organism?

It allows for Genus, the first part, to indicate shared characteristics. As well as Species to show the unique traits of an organism

Organic compounds

contain carbon and hydrogen

Inorganic compounds

may contain carbon, but will lack the associated hydrogen

ionic bond

electrostatic force of attraction that exists between oppositely charged ions

covalent bonds

exists between atoms that share electrons

hydrogen bonds

noncovalent electrostatic attraction between two or more molecules or two or more regions within a single large molecule

what are carbohydrates building blocks and bonds?

building blocks are simple sugars (monosaccharides)

bonds is glycosidic bonds

what are nucleic acids building blocks and bonds?

building blocks are nucleotides

bonds is phosphodiester bonds

what are proteins building blocks and bonds?

building blocks are amino acids

bonds are strong covalent bonds and weak non-covalent interactions

what are lipids building blocks and bonds?

building blocks are glycerol and up to fatty acids

bonds is ester bonds

bacteria plasma membrane

ester bonds join linear fatty acid tails to glycerol

bacteria cell wall

made of peptidoglycan, which provides rigidity

categorized as Gram-positive or Gram-negative

Archaea plasma membrane

use ester bonds to link glycerol to long-branched lipids called isoprenoids

Archaea cell wall

Lack peptidoglycan

may have pseudopeptidoglycan or other polymers that provide structural support.

Gram positive cell wall:

Membrane?

Peptidoglycan layer? If so, where?

lack outer membranes

have a thick peptidoglycan layer in their cell walls

gram negative cell wall

Membrane?

Peptidoglycan layer? If so, where?

have an outer membrane

thin peptidoglycan layer in their cell walls

Acid-fast cell wall:

What does it contain?

contain an external layer of waxy mycolic acids.

flagella function

used for motility, or movement

Fimbriae function

adhesive properties help prokaryotes stick to surfaces or to each other for establishing biofilms or for invading a host

Pili function

used to adhere to surfaces, move, and they can aid in gene transfer through conjugation

Glycocalyx function

helps bacteria stick to host tissues to establish infections

encourages adhesion for biofilm formation

Nucleoid structure

somewhat centralized region

boundaries are not distinct because it isn't enclosed by a membrane

Endospores structure

the core is surrounded by several protective layers, including a dense coat and a high concentration of dipicolinic acid

Endospores function

metabolically inactive structures that allow certain cells to enter a dormant state

Endosymbiotic theory

a series of sequential, cell-merging events between an ancient eukaryotic ancestor and certain prokaryotes

type of DNA located in organelles that support the endosymbiotic theory.

circular DNA in both mitochondria and chloroplasts, similar to bacterial DNA

prokaryotic cells:

Uni or multicellular

Size?

Nucleus?

sterols?

only unicellular archaea and bacterial

usually smaller

no nucleus

rarely contain sterols

eukaryotic cells:

Size?

Structurally complex?

Size and location of genomes

usually larger

structurally more complex than prokaryotic cells

larger genomes that are spread across multiple linear chromosomes

Roundworm:

Shape

Digestive system

What does their lifecycle look like?

cylindrical in shape

have a complete digestive system, which includes a mouth and an anus

known for their complex life cycles, which can involve multiple hosts.

Flatworm:

Subcategories?

Shape and digestive system?

What lifecycle does their subcategory have, and which one?

Structure and location of subcategory and which one?

includes two subcategories: trematodes and cestodes.

Flatworms are generally flattened and have a simple digestive system.

Trematodes often have complex life cycles involving snails as intermediate hosts.

Cestodes are segmented and can grow very long, residing in the intestines of their hosts

Conidiospores

Chains of spores; not enclosed in a sac

Sporangiospores

Spores formed within a sac called a sporangium

Zygospores

Haploid gametes found at the tips of hyphae

Ascospores

Haploid gametes form within a sac called an ascus

Basidiospores

Bud off of a pedestal structure called the basidium

amoeboid

classified based on them using extensions of their cytoplasm to move

flagellated

they have one or more flagella for movement

Spore-forming

they move by gliding and do not have flagella, cilia, or psuedopodia

rough endoplasmic reticulum

mainly involved in protein production, modification, and folding

smooth endoplasmic reticulum function

is central to lipid production and detoxification

Golgi apparatus function

modifies cellular proteins, builds lipids, and further sorts and distributes the finished products; central to secretion

Mitochondria function

generate most cell ATP

Nucleus function

houses the cell's DNA and serves as the cell's command center

Nucleolus function

site where ribosomal subunits begin their development

Leading strand in DNA replication

DNA polymerase III synthesizes the new strand continuously in the same direction as the unwinding of the DNA helix.

Only one RNA primer is needed to initiate replication.

DNA polymerase III extends the strand, and DNA polymerase I replaces the RNA primer with DNA.

Ligase seals the junction.

Lagging strand in DNA replication

Synthesized in short segments called Okazaki fragments, as it proceeds in the opposite direction of helix unwinding.

Requires multiple RNA primers, one for each Okazaki fragment.

DNA polymerase III synthesizes each fragment, DNA polymerase I replaces RNA primers with DNA, and ligase joins the fragments.

Helicase function

Unwinds DNA helix

Primase function

Builds RNA primers; multiple primers are required to build the lagging strand

DNA polymerase III function

Main enzyme that copies DNA on the leading and lagging strand

DNA polymerase I function

Replaces RNA primers with DNA; also has a role in DNA repair

Ligase function

Forms phosphodiester bonds to seal nicks in the DNA sugar-phosphate backbone; important in DNA replication and DNA repair

Gyrase and Topoisomerases function

Relieve torsion stress that develops ahead of helicase as DNA unwinds

transcription:

What is an operon

What does it include

cluster of genes under the control of a single promoter

Includes structural genes, promoter, and an operator

Transcription:

What is RNA polymerase

Enzyme that synthesizes RNA from a DNA template, moving in the 5 to 3 direction

Translation:

mRNA

Carries genetic information from DNA to ribosomes

translation: tRNA

brings amino acids to ribosomes, has codon loops for matching mRNA

Translation: rRNA

Combined with proteins to form ribosomes, facilitating peptide bond formation between amino acids

Translation: parts of a ribosome

Composed of large and small subunits with three sites. E(exit), P(peptidyl), and A(acceptor)

Translations: location of peptide bond formation

P site where rRNA catalyzes the bonding between amino acids during protein assembly

Silent mutations

Substitution mutations that do not change the amino acid sequence of a protein

Missense mutations

the meaning of the codon is changed in a way that the wrong amino acid is added to the growing protein

nonsense mutations

A mutation that causes a codon to go from encoding an amino acid to encoding a stop signal

Frameshift mutations

the reading frame of an mRNA is altered due to nucleotides being inserted or deleted from the coding region of a genetic sequence.

Transformation gene transfer

uptake of free DNA from the environment by a bacterial cell.

Transduction gene transfer

virus transfers genetic material between bacteria

Conjugation gene transfer

genetic material is transferred from one bacterium to another through direct contact

Lac Operon

consists of three structural genes that help the bacterium digest lactose, but it is only activated under specific conditions: when lactose is present and glucose is absent.

capsid structure

protein shell that encases the genetic material of a virus.

can be helical (hollow tube) or icosahedral (three-dimensional polygons). The shape is based on how the capsomeres, are arranged

capsid function

virion formation

represent potential targets for antiviral drugs due to their central role in virus assembly and infection processes.

envelopes viral structure

lipid-based layers that surround the capsid of some animal viruses

acquired by budding from the host cell, taking a portion of the cell membrane as a coating.

Enveloped viruses function

helps the virus evade the host's immune system

assists in the attachment to host cells

use spikes on their surface to bind to receptors on host cells, facilitating entry.

spikes structure

Viral spikes, also known as peplomers, are glycoprotein extensions found on the surface of many viruses

protrude from either the viral capsid or the viral envelope, if present

Explain the features of bacteriophage lytic replication.

Attachment

Penetration

Replication

Assembly

Release

Attachment: bacteriophage binds to the bacterial cell using tail fibers.

Penetration: phage injects its genetic material into the host cell

Replication: phage commandeers the host's machinery to produce viral components, breaking down the host's DNA

Assembly: New phage particles are assembled from the replicated components

Release: The host cell bursts, releasing new phages to infect other cells

Explain the features of bacteriophage lysogenic replication.

Attachment

penetration

Integration

Cell division

Lyric

Attachment: The bacteriophage binds to the bacterial cell using tail fibers.

Penetration: The phage injects its genetic material into the host cell

Integration: After penetration, the phage genome integrates into the host genome, forming a prophage

Cell Division: The prophage is copied along with the host genome during cell division, spreading the phage genome without killing the host

Lytic Cycle Entry: If the host is stressed, the prophage may exit the host genome and enter the lytic cycle, allowing replication and release

general steps of animal virus enveloped

can enter the host cell through membrane fusion or endocytosis, capsid is degraded by host enzymes in the cytoplasm after fusion, and typically bud off from the host cell, acquiring a portion of the host's membrane as their envelope

general steps of animal virus naked

enter the host cell via endocytosis, capsid is broken down by enzymes within the endocytic vesicle, and are usually released by lysing the host cell, which often results in cell death.

what are prions

misfolded proteins that cause spongiform encephalopathies, which destroy brain tissue

what can prions cause

Creutzfeldt-Jakob disease (CJD), Alzheimer's, Parkinson's, and ALS

how is prions transmitted

inheritance

consuming meat with prions

spontaneously

accidentally transmitted through medical procedures

four stages of bacterial growth in a closed batch system

lag phase

log phase

stationary phase

death phase

lag phase

bacterial growth may pause when suddenly moving from nutrient-poor to nutrient-rich conditions.

Steady line at the beginning of the graph

log phase

If the growth conditions are optimized, then once the cells have adjusted, they will enter a phase of rapid exponential growth.

It is characterized by an upward-sloped line that results when the number of viable cells is plotted on a logarithmic scale as a function of time.

stationary phase

at some point available nutrients are depleted, and waste products accumulate. the population growth rate slows and eventually levels off as the number of cells dying matches the number of cells dividing

death phase

At a critical point of waste buildup and decreasing nutrients, the cells in a closed batch culture system begin to die. The rate of cell death is exponential

mesophiles

prefer moderate temperatures and tend to grow best around 10-50C, a range that includes body temperature.

most pathogens are part of the mesophilic temperature group

cover a broad range of the planet, dwelling in soils, streams, and eukaryotic organisms

Psychrotrophs

grow at about 0-30C

associated with foodborne illness because they grow at room temperature as well as in refrigerated and frozen foods.

Acidophiles

can grow at pH 1 (or less) to pH 5 and live in areas such as sulfur hot springs and volcanic vents.

Halophiles

Organisms that thrive in high-salt environments.

tolerate environments that are up to 35 percent salt

Obligate Aerobes

require oxygen for their metabolism and cannot survive without it

Obligate Anaerobes

do not use oxygen and often die in its presence due to their inability to eliminate ROS

Microaerophiles

use small amounts of oxygen and can manage low levels of ROS

Aerotolerant Anaerobes

do not use oxygen, they tolerate its presence and can deactivate ROS

facultative anaerobes

can switch between aerobic and anaerobic metabolism, preferring oxygen but surviving without it

UV radiation

can change the bond structure of DNA, leading to severe mutations that ultimately result in cell death.

UV light boxes in air-handling systems can reduce the number of airborne microbes

they also can be used to sanitize drinking water and swimming pools.

ionizing radiation

high-energy waves generate reactive ions that kill microorganisms and inactivate viruses by damaging their nucleic acids

alcohols: mode of action

Target proteins and lipid membranes

Alcohols: pros

Cheap, easily applied, usable as disinfectant and antiseptic